With increasing age and/or as a consequence of certain diseases, the body's soft tissues, including muscle and fat can diminish, affecting appearance and/or diminishing function. For example, sphincter muscles that control many of the body's autonomic functions such as control of bladder function and gastric reflux diminish with age or disease. Several medical fillers have already been developed such as injectable bovine collagen. This filler has several drawbacks relating mainly to the risk of allergy, and the threat raised by the Kreutzfeld Jacob's disease. As an alternative for injectable bovine collagen, other fillers have been developed such as an implant comprising a particle suspension or emulsion of particles of a polymer comprising lactic acid and/or glycolic acid repeat units (US 2003/093157 or WO 98/56431).
However, the filler as disclosed in each of these patent applications has several drawbacks: the mixing and flowing properties (i.e. flow injectability) of a gel comprising such filler are not optimal due to final product constitution.
Therefore, there is still a need for a slowly resorbing biodegradable medical or cosmetical implant that will not cause any undesired reactions in the human body and that will have superior properties such as flowing properties because of essentially spherical microspheres which avoid aggregation, needle clogging, and nodule forming when injected.